1. Field
Exemplary embodiments of the present invention relate to a method for fabricating a semiconductor device, and more particularly, to a mask pattern for hole patterning and a method for fabricating a semiconductor device using the same.
2. Description of the Related Art
In a DRAM fabrication process, since a hole patterning process using parameters of 30 nm or below is below the resolution of a scanner, holes may be defined by performing a spacer patterning technology (SPT) process twice in directions crossing each other, respectively. The hole patterning process may include a process for defining contact holes or holes to form storage nodes. The hole patterning process is performed into a cell matrix region.
A spacer patterning process may be a positive SPT (PSPT) process or a negative SPT (NSPT) process. The positive SPT (PSPT) process is a process in which spacer patterns are used as an etch mask. The negative SPT (NSPT) process is a process in which an etch mask substance is filled between spacer patterns, the spacer patterns are removed and the etch mask substance is used as an etch mask.
For hole patterning, the positive SPT (PSPT) process may be performed twice or the negative SPT (NSPT) process may be performed twice.
In the case of performing the positive SPT (PSPT) process twice, since a peripheral region is entirely open, a periphery-close mask (PCM), which covers the peripheral region, may be used. However, because an overlay (O/L) margin may not be sufficient, poor patterning may occur in an edge region of a cell matrix region. Conversely, in the case of performing the negative SPT (NSPT) process twice, although a PCM is not necessary, patterning is difficult because the structure of an etch mask formed in the peripheral region is complicated.
Since the positive SPT (PSPT) process has a structure in which the peripheral region is entirely open, etching of the peripheral region may be prevented by adopting the PCM. However, holes may be defined partially or defined in an undesired manner since an overlay between the PCM and the cell matrix region may not be sufficient. Here, even when holes are defined, poorly shaped holes may be formed. These holes are likely not to be open in a subsequent process or result in poor patterns.